The use of interference fit cylinder liners in internal combustion engines provides long engine life and reduce service requirements. Such liners, however, have certain drawbacks as presently fit and sealed within a counterbore of the engine block. In present arrangements, the cylinder head is clamped to the engine block for sealing a head gasket therebetween. A combustion gas seal for the cylinder liner is also clamped between the liner and the cylinder head to seal the combustion gases. In some cases the combustion seal is formed as part of the head gasket. Such arrangements require a high unit loading to effect a seal between the head gasket, the cylinder head and the engine block. Such loadings are transferred to the a cylinder liner flange supported on the cylinder block at a counterbore therein. The high unit loadings are concentrated through the liner flange into the block at the counterbore. Such load concentrations can cause the block to crack at the counterbores therein where the liner flanges engage the block.
An alternative approach has been to eliminate the cylinder block counterbores by providing a separate spacer plate on top of the cylinder block to distribute the cylinder head load into the cylinder block without concentrating the flange liner to cylinder block load on one part of the cylinder block. Such separate spacer plates are an additional cost and require special handling during assembly which further adds complexity and cost of cylinder liner arrangements for use in for high compression internal combustion engines.
Other alternative approaches have been to provide mid-stop or bottom stop surfaces on the cylinder block to receive either a mid flange or an end surface of a cylinder liner. Such arrangements provide more compliance in the liner to take up the high unit loadings when the cylinder head is clamped to the cylinder block. This alternative causes the cylinder block to be placed in tension which in the case of cast iron blocks in the weakest mode of load support.
In each of the aforesaid liner configurations, the cylinder liner is subjected to loadings and moments which will cause the inner surface of the liner to distort. Such distortion results in undesirable oil consumption, piston ring wear, and increased liner wear.
Another approach has been to provide a cylinder liner in which the liner is press fit into a counterbore in a cylinder head. Examples of such arrangements are set forth in U.S. Pat. Nos. 3,937,201 and 4,399,783. The '201 patent requires that the end of the cylinder liner and the cylinder counterbore be precisely dimensioned such that thermal expansion between the liner and cylinder head will effect a tight seal therebetween. The problem with the '201 arrangement is that no combustion gas seal is formed until the engine is thermally expanded. Additionally, once thermally expanded distortion loads are placed on the cylinder liner. The '783 patent is arranged to produce a radial interference fit between the end of the liner and the surfaces of a counterbore in the cylinder head. As assembled the liner of the '783 patent will be distorted at the top of the liner as much or more than the earlier referenced liner assemblies set forth above.
The cylinder liner of the present invention provides for combustion gas sealing in high compression engines and in particular it provides for sealing of combustion gas in high compression diesel engines without distorting the liner and without overloading the cylinder block of the engine to produce undesirable cracks therein.